Packet-switching facilities of this kind are known, e.g., from A. Thomas, J. P. Coudreuse, M. Servel, "Asynchronous Time-Division Techniques: An Experimental Packet Network Integrating Videocommunication", ISS '84 Florence, 7-11 May 1984, Session 32C, Paper 2, pages 1-7 (ISS=International Switching Symposium).
Messages of random volume are preferably transmitted in the form of packets of equal length over virtual circuits. At present it is assumed that messages of deterministic volume will be transmitted in the same manner and together with the other messages.
In a packet-switching facility it may happen that two or more packets intended to be forwarded on the same line arrive simultaneously on different lines.
Therefore, buffers must be provided in which the packets that cannot be forwarded immediately can wait. The amount of storage needed for this purpose, besides depending on the length of the packets, depends particularly on the number of incoming lines, the type of traffic, and the required transmission quality. In prior-art packet-switching facilities, about 80% of the area of all chips in the switching network are used for these buffers. From "Der Fernmelde=Ingenieur", Vol. 41, No. 9, September 1984, especially item 3.4 on pages 8 and 9, and No. 10, October 1987, packet-switching systems are known in which information is transmitted in the form of frames containing fixed numbers of packets. European Patent Publication No. EP-A2-0 125 744 "Closed Loop Telecommunication System" describes a ring system in which a complete frame containing a plurality of packets circulates at all times, using shift registers or other memories.